导　　师： 陈国明

学科专业： 080203

授予学位： 博士

作　　者： ;

机构地区： 中国石油大学华东

摘　　要： 我国对石油资源需求的增加促进了海洋石油工业的发展。随着海上油田开发的不断深入,也出现了与陆上油田相似的诸多问题,如高漏失井、水敏性油藏、油层压力降低等。泡沫流体由于密度小且易于控制、静液柱压力低、粘度高、携带能力强、对油气层伤害小等优点,特别适合这些情况下的钻井、完井、修井等作业。为了将泡沫流体推广应用于海上油田,有必要结合海上油田开发的特点和需要,研究和开发海上油田氮气注入系统。 基于海洋油田开发的环境特点和安全需求,选择海水和氮气作为泡沫流体的液相和气相。采用了Ross-Miles方法和Warning-Blender法对油田常用的发泡剂进行了性能评价,并考察了矿化度、原油、温度等因素对发泡性能的影响,确定了适于海上油田应用的发泡剂产品,并通过实验确定了应用时的最佳浓度。同时根据稳定性实验确定了与发泡剂配合使用的稳定剂体系。 通过实验,研究了温度、压力和气液质量比对泡沫流体密度的影响,根据对实验数据回归得到了不同气液质量比下泡沫流体密度与压力和温度关系的计算关联式,并将计算结果与实验数据、常规计算方法进行对比。利用六速旋转粘度计测量了泡沫流体的粘度。实验表明,各种发泡剂浓度下泡沫流体的流变模式均为幂律模式,通过对实验数据处理得到了满足石油工程应用的泡沫流体流变参数的计算式。 研制出适用于海洋平台及陆上油田使用的氮气泡沫注入系统,其中自行设计的泡沫发生器具有结构简单、耐高压、耐腐蚀、能够连续制备泡沫的优点,可用于各种复杂条件下的施工作业;根据模糊控制理论开发的自动控制系统实现了对氮气泡沫注入系统的实时监控和调节,保证了泡沫发生系统的可靠性,提高了系统的安全性。 根据质量守恒、动量守恒和能量守恒分别建立泡沫流体在油管内和环空中流动时描述其密度、压力、温度变化的数学模型。采用四阶Runge-Kutta方法对油管内的流动进行了求解。计算表明,井筒内泡沫流体的密度、压力和温度是相互影响的,必须根据温度、压力确定泡沫流体的密度。特别是在大泡沫质量的情况下,对深井和超深井不能忽略温度变化对泡沫流体性能的影响。 为了将氮气泡沫注入系统应用于海上油田,利用FLUENT软件计算分析泡沫流体的携砂能力,建立泡沫冲砂洗井的数学模型,采用“恒定环空回压”的迭代方法进行了求解,并编制相应的计算机软件。根据海上油田作业生产的特殊要求,设计开发相应的工艺流程,并进行现场试验和应用。现场应用表明,以泡沫流体作为冲砂洗井工作液,不但能够有效地实现相关的工艺目标,而且具有降低漏失量、减少污染、用量少等优点;研制开发的海上氮气泡沫注入系统安全性、可靠性和适应性好,具有良好的经济效益和推广应用价值。 The increasing need for petroleum resource of China promotes the development of offshore petroleum industry. As the development of offshore oil-filed, similar problems as in land oil-field were also appeared, such as high absorption wells, water-sensitive formation, pressure loss of oil reservoir and so on. Foam fluid is suitable for the drilling, well completion and well workover for such oil-field because of its low density, low static fluid column pressure, high viscosity, strong carrying capacity and weak reservoir damage. In order to popularize the foam fluid to the offshore oilfield, it is necessary to develop a set of injection system of nitrogen gas foam for offshore oil-field combining with its need and characteristic. According to the environment of offshore oil-field and safty demand, sea water and nitrogen gas were selected as the liquid phase and gas phase of foam fluid respectively. The Ross-Miles method and the Warning-Blender method were adopted in laboratory to evaluate the performace of some usual foam agents. The influence of salinity, crude oil and temperature on performance of foam agent was investigated. Foam agent product and the optimum concentration were determined by experiment. Stabilizer system fitting with the foam agent was selected by stability experiment. The effect of temperature, pressure and mass ratio of gas and liquid on foam density was investigated by experiments. Calculation correlations for different mass ratio of gas and liquid were obtained by matching the experimental data. The comparison among the calculation results, experimental data and the results from routine method was conducted. Foam viscosity was measured with six-speed rotary viscosimeter. The results showed that the rheological model of foam fluid was consistent with the power-law model. The expressions of rheological parameters of foam fluid were obtained by matching the experimental data. Injection system of nitrogen gas foam for offshore platform and land oil-field was developed. Foam producer designed autonomously had the merits of simple structure, strong corrosion and pressure resistant and continuous working. It can be used to complex operation conditions. The autocontrol system based on fuzzy control theory can be used to realize real time monitoring and controlling, which can assure the reliability and safty. The mathematical models of the foam density, pressure and temperature for the foam flowing in well bore were set up based on the principle of mass conservation, momentum conservation and energy conservation. Four-order Runge-Kutta method was adopted to solve the model of foam flowing in tubing. The results showed that the foam density, pressure and temperature were influenced each other. The determination of foam density should be based on pressure and temperature. The influence of temperature on foam performance must be considered for deep wells and super-deep wells at high foam quality. In order to apply the injection system of nitrogen gas foam to offshore oilfield, the carrying capability of foam fluid was analyzed by software of FLUENT. A mathematical model for well cleanout of sand washing was obtained. The model was solved by iterative method of constant annular back-pressure and corresponding software was programmed. Process flow was designed according to the special requirement of offshore oil-field and field applications were carried out. Application experience showed that the sand washing by foam fluid, not only the technical goal can be achieved efficiently, but it has the merits of lowering leakage, reducing pollution and volume. The safty, reliability and adaptability of the injection system of nitrogen gas foam were excellent. The system and the corresponding technology had good economic benefit and deployment value.

关 键 词： 泡沫流体 注入系统 泡沫发生器 非牛顿流体 冲砂洗井

分 类 号： [TE357.4]

领　　域： [石油与天然气工程]